Integrated ECG Electrode and Antenna Radiator

ABSTRACT

Multiple circuits in a computing device can share one or more conductive elements. The use of the conductive element can vary by circuit, such as an antenna radiator for a radio frequency (RF) circuit or an electrode for an electrocardiography (ECG) circuit. The circuitry sharing a conductive element can utilize signals obtained over different frequency ranges. Those ranges can be used to select decoupling circuitry, or elements, that can enable the respective circuits to obtain signals over a respective frequency range, excluding signals over one or more other frequency ranges corresponding to other circuitry sharing the circuit. Such an approach allows for concurrent independent operation of the circuitry sharing a conductive element.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Non-Provisional patent applicationSer. No. 16/457,337 filed Jun. 28, 2019 and entitled “INTEGRATED ECGELECTRODE AND ANTENNA RADIATOR” which said application claims priorityto and the benefit of U.S. Provisional Patent Application No.62/697,844, filed Jul. 13, 2018, which are all hereby incorporated byreference herein in their entirety.

BACKGROUND

Recent advances in technology, including those available throughconsumer devices, have provided for corresponding advances in healthdetection and monitoring. For example, devices such as fitness bands andsmart watches are able to determine information relating to the healthof a person wearing the device. It is desirable to be able to provide asmuch functionality as possible, but the limited form factor of thesedevices makes it challenging to include the necessary components.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments in accordance with the present disclosure will bedescribed with reference to the drawings, in which:

FIG. 1 illustrates an example device that can be utilized in accordancewith various embodiments.

FIGS. 2A and 2B illustrate general components of a shared ECG circuitryand electrode system that can be utilized in accordance with variousembodiments.

FIG. 3 illustrates a first example implementation that can be utilizedin accordance with various embodiments.

FIG. 4 illustrates a second example implementation that can be utilizedin accordance with various embodiments.

FIG. 5 illustrates a third example implementation that can be utilizedin accordance with various embodiments.

FIG. 6 illustrates components of an example device that can be utilizedin accordance with various embodiments.

FIG. 7 illustrates an example process for implementing a sharedelectrode assembly that can be utilized in accordance with variousembodiments.

FIGS. 8A and 8B illustrate another example antenna design for acomputing device that can be utilized in accordance with variousembodiments.

FIG. 9 illustrates components of an example computing device that can beutilized in accordance with various embodiments.

DETAILED DESCRIPTION

In the following description, various embodiments will be described. Forpurposes of explanation, specific configurations and details are setforth in order to provide a thorough understanding of the embodiments.However, it will also be apparent to one skilled in the art that theembodiments may be practiced without the specific details. Furthermore,well-known features may be omitted or simplified in order not to obscurethe embodiment being described. Incorporated by reference, in itsentirety, is “METHODS AND SYSTEMS FOR COMBINATION ELECTRODES FORWEARABLE DEVICES,” filed Jun. 28, 2019.

Approaches in accordance with various embodiments provide for theconcurrent and independent operation of circuits of a computing devicethat share at least one conductive element. These can include circuitsfor communication, such as antenna circuits, as well as circuits formaking biometric or physiological measurements for a user. The use ofthe conductive element can vary by circuit, such as an antenna radiatorfor a radio frequency (RF) circuit or a dry electrode for anelectrocardiography (ECG) circuit. The circuitry sharing a conductiveelement can utilize signals obtained over different frequency ranges.Those ranges can be used to select decoupling circuitry (or elements)that can enable the respective circuits to obtain signals over arespective frequency range and exclude signals over one or more otherfrequency ranges corresponding to other circuitry sharing the circuit.Such an approach allows for concurrent independent operation of thevarious circuits sharing a conductive element.

Various other functions can be implemented within the variousembodiments as well as discussed and suggested elsewhere herein.

FIG. 1 illustrates an example wearable device 100 that can be utilizedin accordance with various embodiments. In this example the device is asmart watch, although fitness trackers and other types of devices can beutilized as well. Further, although this device is shown to be worn on auser's wrist there can be other types of devices worn on, or proximateto, other portions of a user's body as well, such as on a finger, in anear, around a chest, etc. For many of these devices there will be atleast some amount of wireless connectivity, enabling data transferbetween a networked device or computing device and the wearable device.This might take the form of a Bluetooth connection enabling specifieddata to be synchronized between a user computing device and the wearabledevice. A cellular or Wi-Fi connection can be used to transmit dataacross at least one network such as the Internet or a cellular network,among other such options.

As mentioned, there can be various other types of functionality offeredby such a wearable device, as may relate to the health of a personwearing the device. One such type of functionality relates toelectrocardiography (ECG). ECG is a process that can be used todetermine and/or track the activity of the heart of a person over aperiod of time. In order to obtain ECG data, a conductive electrode isoften brought into contact with the skin of the person to be monitored.In the example situation of FIG. 1 , a person is wearing a wearabledevice 100 on his or her arm 102, and can bring one or more fingers 106(or palm, etc.) into contact with an exposed electrode of the device. Inthis example, the electrode is at least a portion of a metallic ring 104that is part of the housing around a display screen 108 of the wearabledevice, although other types and forms of electrodes can be used as wellwithin the scope of the various embodiments. The electrode can beconnected to an ECG circuit that can detect small changes in electricalcharge on the skin that vary with the user's heartbeat. ECG data can bemonitored over time to attempt to determine irregularities in heartbeatthat might indicate serious cardiac issues. Conventional ECGmeasurements are obtained by measuring the electrical potential of theheart over a period of time, typically corresponding to multiple cardiaccycles. By a user placing his or her fingers on the exposed electrodefor a minimum period of time, during which ECG measurements are taken,an application executing on the wearable device can collect and analyzethe ECG data and provide feedback to the user.

As mentioned, however, space for additional elements in such a devicecan be limited. There may be other relevant considerations as well, asmay relate to weight, resource costs, manufacturing capabilities, orappearance. These limits must be balanced with the needs or desires tosupport multiple communications protocols, as may include Bluetooth,Wi-Fi, GNSS, and LTE Cat-M1, among others. The ability to concurrentlysupport multiple communications protocols in some embodiments canbenefit from the use of multiple antennas. Each additional antenna,however, requires space on, or in, the device. It therefore can bedesirable to attempt to reduce or minimize the number of elementsrequired. When measuring ECG as discussed above, an electrode can beused that can take the form of a large metal element, or other elementof a sufficiently conductive material. Since the ECG frequencies aresufficiently different than the frequencies for the variouscommunications protocols, approaches discussed herein can utilize one ormore ECG electrodes as communications antenna elements. Such an approachcan reduce the number of elements (including separate antenna(s) andelectrode(s)) needed to support the same functionality on a specificdevice.

FIG. 2A illustrates a simplified block diagram 200 of one suchimplementation that can be utilized in accordance with variousembodiments. This diagram illustrates antenna matching circuitry 202 andECG circuitry 210, which each can include any appropriate circuitryknown, used, or appropriate for such functionality, including but notlimited to those discussed herein. The antenna matching circuitry 202and ECG circuitry 210 can share a single electrode 206 in this example,although other combinations or approaches can be used as well within thescope of the various embodiments. For many ECG implementations, at leastone electrode 206 must be isolated from extended contact with the skinof the user, such as from the wrist upon which a smart watch or fitnesstracking device might be worn. An example electrode is metallic and of asufficiently large size, at least relative to the size of the device, inorder to allow for good contact with the skin of the user. In oneexample embodiment, an electrode has a size on the order of at least 150mm². Such electrode can be made of stainless steel, although anyconductive metal material or metal alloy may be considered as long asthe contact surface is not subject to oxidation during exposure to airor moisture. Where multiple communication protocols or standards areutilized, the antenna radiators may need to occupy a large portion ofthe volume within or on the device. The antenna circuitry is typicallyplaced relatively close to the antenna radiator or electrode, whilethere may be no restriction or advantage to placing ECG circuitryrelatively close to the antenna circuitry. The ECG circuitry can beplaced at an optimal location for the particular device design. Anapproach such as that illustrated in FIG. 2A enables at least onemetallic piece, or other conductive element, to be utilized concurrentlyas an ECG electrode and an antenna radiator. As discussed elsewhereherein, additional circuits that utilize similar conductive elementsmight share such an element as well, such as where the frequency rangeto be analyzed for a circuit or application falls sufficiently outsidethe frequency range of any other circuit or application sharing aparticular electrode. There may also be more than two circuits sharing asingle conductive element, or set of conductive elements, within thescope of the various embodiments. The sharing of such components cansave significant space on, or within, such a device where separateelements of this size might otherwise be required.

In the example system of FIG. 2A, the ECG circuitry 210 is connected tothe shared electrode 206 (also functioning as an antenna radiator) via adecoupling circuit or element 208 that isolates the ECG circuitry 210over a range of radio frequency (RF) frequencies (around 700 MHz toaround 3 GHz, or above 600 MHZ for at least some embodiments utilizingLTE Cat M1, GNSS, Bluetooth, and Wi-Fi protocols, or up to about 6 GHzin other embodiments) from the antenna matching circuitry 202, which canbe connected to one or more RF systems. The antenna matching circuitry202 can be connected to the shared electrode/radiator 206 via a seconddecoupling circuit or element 204 that isolates it at a range of lowfrequencies (around 0 Hz (DC) to around 150 kHz for some embodiments,although for sufficient isolation a higher cutoff frequency can beutilized) from the ECG circuitry 210. The impact of the ECG circuit onthe antenna matching circuit can be reduced by using inductors orferrite beads that have high impedance at RF frequencies instead of highimpedance resistors as discussed elsewhere herein. Since ECG circuitrieshave high impedance inputs, the relatively lower impedance decouplingcomponent 208 will have a negligible impact on the ECG system in atleast some embodiments. Additional isolation can be achieved in someembodiments by using a shunt capacitor to ground after the seriesresistor/inductor that would present a short circuit to ground at RFfrequencies. By achieving good isolation at their respective frequenciesof operation between the ECG circuit and antenna matching circuit withthe first few components of each circuit, other parts of the ECG circuitcan be more easily designed and optimized without affecting the antennamatching circuit, and vice versa. Decoupling the circuits also enablesthem to function independently in at least some embodiments, although inother embodiments the conductive elements might be shared but onlyoperated one at a time for a specific circuit, such as where a specificcommunication protocol utilizes a frequency range that is relativelyclose to that of the ECG circuit or other circuit sharing the conductiveelement. If there are more than two circuits sharing such an element,then any subset of the circuits that are decoupled can concurrentlyutilize the element at a specific time.

Decoupling elements can be used to filter or otherwise attenuate signalsfrom one circuitry element to another. For example, one decouplingelement can cause the ECG signal to not significantly load thecommunications circuitry (and/or vice versa), providing a few tenths ofa decibel of load (e.g., 0.1 dB, 0.2 dB, 0.3 dB, 0.4 dB, or 0.5).

FIG. 2B illustrates an example alternative to FIG. 2A whereby there aretwo electrodes 206 a and 206 b each connected to respective antennamatching circuitry 202 a and 202 b using respective decouplers 204 a,204 b, 208 a, and 208 b. The two electrodes can then be connected to asingle ECG circuitry element 210.

FIG. 3 illustrates a first example subsystem 300 that can be utilized inaccordance with various embodiments. In this example a conductiveelement 302 is shared as an electrode for an ECG circuit 308 and aradiator for an antenna matching circuit 304. The ECG circuit andantenna matching circuit can be on the same or different printed circuitboards (PCB), chips, etc., in various embodiments. This examplerepresents a monopole antenna concept wherein there is no ground pathfrom the antenna radiator to system PCB ground. In this example, a firstdecoupling element 306 is positioned between the shared conductiveelement 302 and the antenna matching circuit 304, which in turn feedsinto an RF chipset 312. The first decoupling element 306 is selectedbased at least in part upon the relative operating frequencies of theECG circuit and the antenna matching circuit, such that only frequencieswithin the range for the antenna matching circuit are passed along tothe antenna matching circuit 304, or at least that frequencies in therange for the ECG circuit are not significantly passed along to theantenna matching circuit 304. There may be some amount of cross-talkbetween the signals of the two frequency ranges, but such cross-talk isnegligible in some embodiments, or can be accounted for in others. Suchcross-talk can be digitally attenuated as part of a signal analysisprocedure. A second decoupling element 310 can be selected based atleast in part upon the relative operating frequencies of the ECG circuitand the antenna matching circuit, such that only frequencies within therange for the ECG are passed along to the ECG circuit 308, or at leastthat frequencies in the range for the antenna matching circuit are notsignificantly passed along to the ECG circuit 308. Although specificcomponents are illustrated for the ECG and antenna matching circuits, asmentioned elsewhere herein any appropriate circuitry known, used, ordeveloped for such purposes can be utilized as well within the scope ofthe various embodiments. As at least some circuits of these types arewell known in the art, they will not be discussed in detail herein. Inone embodiment, the first decoupling element 306 (or circuit) is a 33 pFcapacitor aligned in series for decoupling of the ECG signal, althoughother capacitors can be used as well in various embodiments, such ascapacitors with values between about 20 pF and about 100 pF, or evenvalues up to 100 nF. The second decoupling element 310 (or circuit) inthis example is a 22k resistor used for RF antenna decoupling, which invarious embodiments is preferred to be placed closer to the conductiveelement 302 in this embodiment. This decoupling element canalternatively be a resistor having a value between 5K ohms and 100Kohms, or an inductor with a value between about 30 nH to about 1 uH insome embodiments, or a ferrite bead which provides 1000 ohms or highimpedance at the operating frequencies of the antenna matching circuit.A second contact point for the ECG circuit 308 as illustrated can beconnected to a second electrode that is not shared with the antennamatching circuit 306. In this example the capacitor of the firstdecoupling circuit 306 provides an open circuit for the signals at theECG frequency, and the resistor of the second decoupling circuit 310will only allow signals at the antenna frequency to pass to the antennamatching circuit.

As discussed herein, the first and second decoupling elements (orcircuits) can be any appropriate decoupling elements capable offiltering out specific frequencies, or allowing only specificfrequencies, to be propagated from a shared conductive element. Thedecoupling elements (or circuits) can include elements such asresistors, inductors, capacitors, and ferrite beads, which can havevalues or ranges as specified herein. As mentioned, the values can bedetermined based at least in part upon the respective circuit to which arange of frequencies are to pass, and other circuits sharing theconductive element whose frequencies are not to pass via the decouplingelement (or circuit).

FIG. 4 illustrates another example subsystem 400 that can be utilized inaccordance with various embodiments. In this example a conductiveelement 402 is shared as an electrode for an ECG circuit 408, via arespective decoupling element 410 (or circuit), and a radiator for anantenna matching circuit 404, via a pair of (or multiple) decouplingelements 406 (or decoupling circuits). In this example, the antenna isof a different type that that of FIG. 3 , being a loop antenna, slotantenna, or inverted-F antenna (IFA), among other such options. For thistype of antenna one or more ground paths are needed from the antennaradiator to the system PCB ground. Two or more decoupling elements 406for the antenna matching circuit 404 can be of the same type ordifferent types. The two or more decoupling elements 406 can have thesame value or different values, such as two or more 33 pF capacitors fordecoupling to the ECG signal. The capacitor range can also be the sameas is discussed with respect to the corresponding capacitors of FIG. 3 .The ECG circuit in this example cannot be DC grounded, whichnecessitates the capacitive element in each ground path.

FIG. 5 illustrates another example subsystem 500 that can be utilized inaccordance with various embodiments. In this example, a conductiveelement 502 of a pair of conductive elements 502, 504 is shared as anelectrode for an ECG circuit 512, via a respective decoupling element514. In this example, an electrode 502 can then function as an antennaradiator which is capacitively coupled through a feeding element 504connected to an antenna matching circuit 510. The electrode 502 has oneor more ground paths to the system PCB ground each via a decouplingelement 508. In this example the antenna is of yet a different type,here being a parasitic antenna or capacitive feed antenna that utilizesa ground path to the parasitic radiator or capacitive feed radiator. Thecapacitive feed antenna can be multiple type of antennas, for example acapacitive feed monopole antenna, a capacitive feed loop antenna, or acapacitive feed slot antenna. A parasitic antenna or a capacitive feedantenna is also referred to as a passive antenna in some situations asit is not electrically connected to anything else, namely any othercircuits on the device. When properly decoupled, the conductive element502 can function as a passive antenna element. In this example at leasta decoupling element 508 is utilized along each ground path, which canbe a capacitor of 33 pF or another such value discussed for suchpurposes herein.

As mentioned, the electrode or other capacitive element(s) can take manyforms on, or in, the device, although for ECG and various otherapplications at least a portion of the electrode must be exposed orotherwise accessible to the skin of the user. In at least someembodiments, the exposed electrode is utilized with one or more otherelectrodes that interface with the skin of the wrist or other suchlocation, as may be based upon the type of device or preference of theuser. As illustrated in FIG. 1 , the electrode can be part of the devicehousing, or part of a conductive ring around a screen or element of thedevice. The electrode can also be one or more rods or planar elementspositioned at a periphery of the device casing, among other suchoptions. Additionally or alternatively, surface-mounted stainless steelstrip can be utilized as an ECG electrode. The electrode strip in oneembodiment is adhered to the outside surface of a metal housing but isisolated from the metal housing by one or more layers of adhesive or anon-conductive polybutylene terephthalate (PBT) material manufacturedusing a process such as nano-molding. As mentioned, for ECG applicationsthis element should not be in contact, or at least extended contact,with the wrist of the user. In some embodiments, nano-molding can beutilized to generate a ring or loop design, where there may be one ormore conductive elements, or elements of one or more pieces or regions.In some embodiments there might be multiple splits, such as maycorrespond to four separate elements, each with a different feed point.Any or all of those elements can be used as electrodes as well, witheach capable of being used for at least one different circuit in someembodiments. For example, a top electrode might be used for ECG andWi-Fi circuitry, while a bottom electrode might be used for LTEcommunications. There may also be multiple conductive elements utilizedfor the ECG circuitry, where each element works with a respectiveantenna circuit, such as for Wi-Fi, 5G, LTE, GNSS, Bluetooth, etc. Insome such embodiments, multiple conductive elements utilized for the ECGare utilized by a single antenna circuit and protocol to take advantageof multipathing of signals received/transmitted by the multipleconductive elements (e.g., multi-stream beamforming, spatialmultiplexing, and diversity coding as well as other multiple-in andmultiple-out (MIMO) or similar techniques). While in many embodimentsmeasurements can be taken concurrently at any time, as discussed in someembodiments where ECG measurements might be taken infrequently, such asonly once per day, it might be beneficial to limit communications duringthat time for a communications circuit utilizing that electrode as anantenna element. For example, the communications circuit can temporarilyimpose a rate limit or a power limit or otherwise stop communicationsexcept for those necessary to maintain the communications link. In someembodiments, certain frequencies or encoding techniques (e.g.,quadrature amplitude modulation or orthogonal frequency-divisionmultiplexing) within a communications specification might not be fullyfiltered by the ECG decoupling element. When ECG measurements are taken,the communications circuitry can minimize use of such frequencies orencoding techniques. For example, a protocol using adaptivefrequency-hopping spread spectrum can be programmed to “skip” overfrequencies that cause problems for ECG measurement.

As mentioned, other designs or types of conductive elements can be usedin accordance with various embodiments. For example, FIG. 6 illustratesa top view of an example electronic device 600 having a metal plate 608within a metal housing 616 forming a slot antenna 610 that is excited bya monopole antenna 606. The housing (such as a metal housing) 616 may bedesigned to accommodate a display that will be worn on a person's wrist.A wristband (not shown) may be connected to the opposing ends of themetal housing, and the completed unit may be worn on someone's wrist.The metal housing may be designed to conform better to thecross-sectional curvature of a person's forearm and the interior of themetal housing may be occupied by various electrical components,including a PCB or FPCB (Flexible Printed Circuit Board) that includes,for example, various sensors, processors, power management components,etc. The metal housing may include additional features, such as a metalbutton bracket 612, to support other elements within the metal housing.

The slot antenna 610 is structured as a gap between the metal plate 608and the metal housing 616 (including the metal button bracket 612)stopped at two ends with grounding contacts 614, 620 between the metalplate and the metal housing. The gap between the metal plate and themetal housing, running between the grounding contacts 614, 620, formsthe slot antenna 610 that, when excited by the monopole antenna 606,radiates or receives RF signals. The slot antenna can be configured as ahalf-wavelength slot antenna (e.g., a length of about 6.25 cm forBluetooth communication). The slot antenna is not directly driven by anyelement (e.g., an antenna feed or coaxial cable) coupled to the printedcircuit board or other similar component. A third grounding pin 618 canbe included to improve performance. The grounding contacts 614, 620 canbe used to tune the slot resonance of the slot antenna (e.g., toresonate within the Bluetooth band). The third grounding pin 618 can beused for reducing or preventing unwanted resonances in the remaining gapbetween the metal housing and the metal plate that may reduce theradiation efficiency of the slot antenna 610. The grounding clips can beconfigured as a spring contact or other type of electrical connection.The grounding clips can include elements that terminate in a leaf springthat presses against the metal housing or metal button bracket.

The example monopole antenna 606 is designed to excite the slot antenna610 in a targeted mode. The monopole antenna includes a flex printedcircuit board (FPCB) as the monopole radiator 602 on a monopole antennacarrier 604 made of a plastic mechanical component. The FPCB 602 isassembled on the surface of the carrier 604 and the carrier is placedinside the metal housing 616. The carrier can be attached to the metalhousing or other component of the device.

Such a device can be used for biometric monitoring in some embodiments,as discussed herein. Biometric monitoring devices, including wrist-wornbiometric monitoring devices, can be configured to send and receivebiometric and other data to and from one or more separate electronicdevices. To wirelessly send and receive data, such monitoring devicesrequire the use of one or more antennas in the device.

An example antenna architecture for wearable electronic devices includestwo portions. First, the antenna architectures include a monopoleantenna having a monopole radiator on a plastic carrier implemented at atop of a display area within a metal housing of the device. The monopoleradiator is connected through an antenna clip on a printed circuit board(PCB) to a radio frequency (RF) engine. The monopole antenna can beimplemented as a flex film antenna radiator assembled on, for example, aplastic carrier. The monopole radiator can generate electromagneticfields to induce the slot antenna to transmit or receive radio frequencysignals. The antenna can be designed to be particularly receptive to (oremissive of) radio frequency energy at frequencies within the frequencyband(s) for the wireless communications protocol(s) that the antenna isdesigned to support, and the antenna can also be designed to not beparticularly receptive to (or emissive of) radio frequency energy atfrequencies outside of the frequency band(s). Antennas may achieve suchselectivity by virtue of their physical geometry and the dimensions thatdefine that geometry.

Second, the antenna architectures include a slot antenna formed by a gapbetween a metal (and/or conductive) plate and the metal housing. Theslot antenna radiates RF signals from the slot structure through adisplay module, a touch module, and a glass window. The monopoleradiator and slot antenna are capacitively coupled such that themonopole radiator generates a varying electric field that inducesvarying electric fields at the slot antenna, resulting in the receptionand/or emission of RF signals. This coupling of electric fields betweenthe monopole radiator and the slot antenna allows for RF signals to betransmitted from and received by the device. The monopole radiator ispositioned within the slot area to excite the slot antenna throughelectromagnetic field coupling. The dimensions of the slot antenna andmonopole antenna can be tuned to achieve targeted communicationfrequency bands. Furthermore, the monopole antenna portion can be tunedto have a certain length and a matching circuit on the PCB may beutilized to tune the antenna impedance to achieve targeted performancecharacteristics. In some embodiments, the metal plate and/or metalhousing can be conductive. The metal plate and/or metal housing caninclude one or more materials that include a conductivity of 1E5Siemens/m and/or higher.

In some embodiments, the disclosed monopole-excited slot antenna reducesthe dead band of the display window or provide a desirably oradvantageously small dead band at a top of the display window. Themonopole antenna component that excites the slot antenna can provide atargeted excitation for the slot antenna with a reduced distance betweena top side of the metal housing and a display module relative to a puremonopole antenna or inverted-F antenna (IFA) architecture with similarantenna performance.

In some embodiments, the disclosed monopole-excited slot antennaaccommodates a device architecture having a printed circuit board (PCB)mounted close to the bottom of a metal housing. For tapered metalhousings, this allows a relatively large battery to be placed above thePCB and within the metal housing. In contrast, devices with similartapered metal housings employing other antenna designs may require thePCB to be mounted above the battery to achieve suitable performance,manufacturing costs, and/or mechanical complexity. In such devices, thebattery size is reduced relative to devices that incorporate the antennaarchitectures disclosed herein that allow the battery to be placed abovethe PCB.

In some embodiments, the disclosed monopole-excited slot antenna designresides entirely within the metal housing. Advantageously, thisfacilitates manufacturing the device to be water resistant and/or swimproof. Where at least some portion of the antenna is exterior to themetal housing, vias, or holes in the metal housing may be required tosend and receive electrical signals to the portion of the antennaoutside of the metal housing. These vias or holes may compromise anywater-tight capabilities of the device or may undesirably increase thecost of making such a device water resistant and/or swim proof.

In some embodiments, the disclosed monopole-excited slot antenna designsexert no contact pressure force on the glass window. Advantageously,this facilitates manufacturing the device to be water resistant and/orswim proof, creating water-tight seals for junctions between components.Where an antenna exerts an outward force on the display window, forexample, the display window may tend to separate from the metal housing,compromising the water-tight seal.

Example monopole-excited slot antenna functions by using acapacitively-coupled monopole antenna radiator to excite an antennaslot. Relative to a device that uses a slot antenna with a direct feedfrom a PCB to excite the slot antenna, the disclosed antenna design maybe advantageous due at least in part to being mechanically simpler(e.g., not requiring the using of a coaxial cable or other transmissionline from the PCB to the antenna) resulting in a lower cost andincreased ease of manufacture.

Various implementations discussed herein may be used, for example, toprovide a monopole-excited slot antenna that provides Bluetoothfunctionality, including Bluetooth Low Energy (Bluetooth LE or BTLE)functionality. Such a compact and efficient antenna may be of particularuse in highly-integrated devices having a small form factor. Forexample, the disclosed antennas can be used in biometric monitoringdevices, e.g., wearable devices that track, report, and communicatevarious biometric measurements, e.g., distance traveled, steps taken,flights of stairs climbed, etc. Such devices may take the form of asmall device that is clipped to a person's clothing or worn on aperson's wrist. Such a device may, for example, contain variousprocessors, printed circuit boards, sensors, triaxial accelerometers,triaxial gyroscopes, triaxial magnetometers, an altimeter, a display, avibramotor, a rechargeable battery, a recharging connector, and an inputbutton all within a metal housing that measures approximately between1.62″ and 2″ in length, 0.75″ and 0.85″ in width, and 0.3″ and 0.44″ inthickness. A monopole-excited slot antenna may be used in such a deviceto provide RF communication in a water resistant and/or swim-proofwearable device, to reduce the dead band of a display window, and/or toprovide a more cost-efficient and mechanically simple device.

Due to the small size of such devices, monopole-excited slot antennas,such as those disclosed herein, may provide the ability to offer a morecompact communications solution than might otherwise be possible,allowing additional volume within the metal housing to be made availablefor other purposes, such as a larger battery. Such dimensions may proveto be particularly well-suited to RF communications in the Bluetoothwireless protocol bands, e.g., 2402 MHz to 2480 MHz.

Monopole-excited slot antenna antennas that support other wirelesscommunications protocols may also be designed using the principlesoutlined herein. For example, the disclosed antenna architectures may beconfigured or dimensioned to be suitable for use with wireless networksand radio technologies, such as wireless wide area network (WWAN) (e.g.,cellular) and/or wireless local area network (WLAN) carriers. Examplesof such wireless networks and radio technologies include but are notlimited to Long Term Evolution (LTE) frequency bands or other cellularcommunications protocol bands, GPS (Global Positioning System) or GNSS(Global Navigation Satellite System) frequency bands, ANT™, 802.11, andZigBee™, for example, as well as frequency bands associated with othercommunications standards. The RF radiator size, gaps between components,and other parameters discussed herein may be adjusted as needed in orderto produce a monopole-excited slot antenna, as described herein, that iscompatible with such other frequency bands.

In some implementations, embodiments involve antenna configurations forbiometric monitoring devices. The term “biometric monitoring device” isused herein according to its broad and ordinary meaning, and may be usedin various contexts herein to refer to any type of biometric trackingdevices, personal health monitoring devices, portable monitoringdevices, portable biometric monitoring devices, or the like. In someembodiments, biometric monitoring devices in accordance with the presentdisclosure may be wearable devices, such as may be designed to be worn(e.g., continuously) by a person (i.e., “user,” “wearer,” etc.). Whenworn, such biometric monitoring devices may be configured to gather dataregarding activities performed by the wearer, or regarding the wearer'sphysiological state. Such data may include data representative of theambient environment around the wearer or the wearer's interaction withthe environment. For example, the data may comprise motion dataregarding the wearer's movements, ambient light, ambient noise, airquality, etc., and/or physiological data obtained by measuring variousphysiological characteristics of the wearer, such as heart rate,perspiration levels, and the like.

In some cases, a biometric monitoring device may leverage other devicesexternal to the biometric monitoring device, such as an external heartrate monitor in the form of an ECG sensor for obtaining cardiovascularinformation, or a GPS or GNSS receiver in a smartphone may be used toobtain position data, for example. In such cases, the biometricmonitoring device may communicate with these external devices usingwired or wireless communications connections. The concepts disclosed anddiscussed herein may be applied to both stand-alone biometric monitoringdevices as well as biometric monitoring devices that leverage sensors orfunctionality provided in external devices, e.g., external sensors,sensors or functionality provided by smartphones, etc.

Below the metal plate is positioned a battery (not shown). The batterycan be secured within the metal housing to maintain its relativeposition within the metal housing. For example, a spacer can be used tomaintain a separation between the battery and the metal housing. Belowthe battery is positioned a component layer on a PCB. The componentlayer can include microprocessors, RAM (random access memory), ROM (readonly memory), ASICs (application specific integrated circuit), FPGAs(field programmable gate array), surface mounted elements, integratedcircuits, and the like. The PCB provides electrical components andcircuitry that directs and interprets electrical signals for the device.For example, the PCB is electrically coupled to the display and touchmodules to interpret touch input and to provide images or information todisplay. The PCB is coupled to an antenna feed clip that is electricallycoupled to the monopole antenna. The PCB can include a ground plane areathat forms a ground plane for the monopole antenna. The PCB can includea feed clip area that does not include conductive elements other thanwhere the antenna feed clip is mounted on and electrically coupled tothe PCB. For example, the PCB can include a trace that electricallycouples the ground plane area to the feed clip area, the feed clip beingelectrically coupled to the trace in the feed clip area. The groundplane for the monopole antenna may be provided by a large metalizedarea, conductive traces in a printed circuit board (e.g., the PCB) orflexible printed circuit board, a metal plate and/or surface within themetal housing, etc. The device can also include a vibrating motor toprovide haptic feedback or to otherwise mechanically vibrate the device.The PCB can be grounded to the metal housing through one or moregrounding screws that electrically couple the PCB to the metal housing.Between the battery and component layer, there is a dielectric gap (e.g.air or plastic or combination of air and plastic) which creates a backcavity for the slot antenna within an enclosed metal housing design. Thedielectric gap may vary in height, but must insure isolation between thebattery to any component on the component layer.

An alternative configuration includes a slot antenna that is directlyfed from the PCB rather than being coupled to a monopole antenna, withthe PCB being placed above the battery. In devices with taperedcross-sections, this may undesirably reduce the size of the battery.Another alternative configuration includes a slot antenna that isdirectly fed from the PCB rather than being coupled to a monopoleantenna, with the PCB below the battery. This would require the use of afeed line (e.g., coaxial cable) from the PCB to the metal plate or metalhousing near the metal plate to excite the fields between the metalhousing and the metal plate. Using a coaxial cable complicates themechanical implementation and increases the cost of the device.Furthermore, the disclosed antenna architectures can be configured toachieve similar performance characteristics as an elevated feed designusing a coaxial cable. Another alternative configuration includes amonopole or IFA antenna outside the metal housing. One drawback of thisdesign is the introduction of additional mechanical complexity and addeddifficulties in achieving a device that is water resistant and/or swimproof. The antenna feed would typically connect the PCB inside the metalhousing to the antenna located outside the metal housing. Accordingly,the disclosed antenna architectures can be housed entirely within themetal housing to facilitate water resistance of the device.

FIG. 7 illustrates an example process 700 for implementing and utilizinga shared conductive element that can be utilized in accordance with oneembodiment. It should be understood for this and other processesdiscussed herein that there can be additional, alternative, or fewersteps performed in similar or alternative orders, or in parallel, withinthe scope of the various embodiments unless otherwise stated. In thisexample, an antenna matching circuit and ECG circuitry are connected 702to at least one shared electrode, antenna radiator, or other suchconductive element. A first operational frequency range is determined704 for the antenna matching circuit, and a second operational frequencyrange is determined 706 for the ECG circuit. A first decoupling element(or circuitry, etc.) can be selected 708 to be placed between the sharedelectrode and the antenna matching circuit, in order to filter out thesecond operational frequency range. A second decoupling element (orcircuitry, etc.) can be selected 710 to be placed between the sharedelectrode and the ECG circuit, in order to filter out the firstoperational frequency range. Taking advantage of these differentfrequency ranges enables a decoupling circuit, or set of decouplingelements, to be used to pick out the frequency ranges of interest foreach circuit, such as where there may be different or other circuitssharing the electrode as well. Once decoupling is in place, the antennamatching circuit and the ECG circuitry can be operated 712 concurrently.The antenna matching circuit can then be enabled 714 to transmit asignal and/or receive a signal using the shared electrode in the firstoperational frequency range, and the ECG circuit can be enabled toreceive input from the shared electrode in the second operationalfrequency range, with minimal cross-talk between the frequency rangesacross the decoupling circuitry. As mentioned, there may be differentnumbers of electrodes or circuitry that can be shared in variouscombinations within the scope of the various embodiments.

As mentioned, the various embodiments can be implemented as a systemthat includes one or more tracking devices for a given user. In someinstances aspects of the embodiments may be provided as a service, whichusers can utilize for their devices. Other tracker providers may alsosubscribe or utilize such a service for their customers. In someembodiments an application programming interface (API) or other suchinterface may be exposed that enables collected body data, and otherinformation, to be delivered to the service, which can process theinformation and send the results back down to the tracker, or relatedcomputing device, for access by the user. In some embodiments at leastsome of the processing may be done on the tracking or computing deviceitself, but processing by a remote system or service may allow for morerobust processing, particularly for tracking devices with limitedcapacity or processing capability.

In some example embodiments, the housing of a device 800, such as afitness tracker illustrated in FIG. 8A, may include a metallic body thatforms at least a part of the boundaries of the cavity 862 and a metallicantenna in close proximity to the cavity 862. As illustrated in the view850 of FIG. 8B, the antenna 852 is located above the metallic body 864.While many internal aspects of the fitness tracker have been omittedfrom this view, a non-metallic material 854, such as a plastic, isillustrated as separating the antenna 852 from the metallic body 864. Insome instances the performance of the antenna may decrease when metallicbodies are positioned within a particular threshold distance or zonefrom the antenna 852. This may be considered a “keep-out” zone whichvaries for different antennas. The metallic body 864 is positioned andshaped so that it is outside the keep-out zone of the antenna 852.Although the metallic body 864 is described as metallic, in someembodiments this aspect of the housing may not be metallic, but rather apolymer, a plastic, a composite, or other material that can form aportion of the housing with suitable strength and rigidity, for example.It was further discovered that when a metallic body was inserted intothe cavity 862 and made contact with the metallic surface of the cavity862, the inserted metallic body became an electric ground for themetallic body 864 which caused the inserted metallic body to be withinthe keep-out zone of the antenna 852 and adversely affected theperformance of the antenna 852. However, it was discovered that if ametallic body was inserted into the cavity 862, was within the keep-outzone, but did not make contact with the metallic surfaces of the cavity862, then the inserted metallic body did not adversely affect theperformance of the antenna 852. Accordingly, some embodiments of theband latch mechanism disclosed herein are intended to be inserted intothe cavity to enable a wristband to be connected to the housing withouthaving a metallic body contact the metallic surfaces of the cavity whilestill maintaining an adequate connection to the housing and havingsufficient robustness, resilience, and strength. Additional detailregarding such an implementation can be found in co-pending U.S. patentapplication Ser. No. 15/820,928, filed Nov. 22, 2017, and entitled “BandLatch Mechanism and Housing with Integrated Antenna,” which is herebyincorporated herein in its entirety and for all purposes.

FIG. 9 illustrates components of an example cycle prediction system 900that can be utilized in accordance with various embodiments. In thisexample, the device includes at least one processor 902, such as acentral processing unit (CPU) or graphics processing unit (GPU) forexecuting instructions that can be stored in a memory device 904, suchas may include flash memory or DRAM, among other such options. As wouldbe apparent to one of ordinary skill in the art, the device can includemany types of memory, data storage, or computer-readable media, such asdata storage for program instructions for execution by a processor. Thesame or separate storage can be used for images or data, a removablememory can be available for sharing information with other devices, andany number of communication approaches can be available for sharing withother devices. The device typically will include some type of display906, such as a touch screen, organic light emitting diode (OLED)display, or liquid crystal display (LCD), although devices might conveyinformation via other means, such as through audio speakers orprojectors.

A tracker or similar device will include at least one motion detectionsensor, which as illustrated can include at least one I/O element 910 ofthe device. Such a sensor can determine and/or detect orientation and/ormovement of the device. Such an element can include, for example, anaccelerometer, inertial sensor, altimeter, or gyroscope operable todetect movement (e.g., rotational movement, angular displacement, tilt,position, orientation, motion along a non-linear path, etc.) of thedevice. An orientation determining element can also include anelectronic or digital compass, which can indicate a direction (e.g.,north or south) in which the device is determined to be pointing (e.g.,with respect to a primary axis or other such aspect). A device may alsoinclude an I/O element 910 for determining a location of the device (orthe user of the device). Such a positioning element can include orcomprise a GPS or similar location-determining element(s) operable todetermine relative coordinates for a position of the device. Positioningelements may include wireless access points, base stations, etc., thatmay either broadcast location information or enable triangulation ofsignals to determine the location of the device. Other positioningelements may include QR codes, barcodes, RFID tags, NFC tags, etc., thatenable the device to detect and receive location information oridentifiers that enable the device to obtain the location information(e.g., by mapping the identifiers to a corresponding location). Variousembodiments can include one or more such elements in any appropriatecombination. The I/O elements may also include one or more biometricsensors, optical sensors, barometric sensors (e.g., altimeter, etc.),and the like.

As mentioned above, some embodiments use the element(s) to track thelocation and/or motion of a user. Upon determining an initial positionof a device (e.g., using GPS), the device of some embodiments may keeptrack of the location of the device by using the element(s), or in someinstances, by using the orientation determining element(s) as mentionedabove, or a combination thereof. As should be understood, the algorithmsor mechanisms used for determining a position and/or orientation candepend at least in part upon the selection of elements available to thedevice. The example device also includes one or more wireless components912 operable to communicate with one or more electronic devices within acommunication range of the particular wireless channel. The wirelesschannel can be any appropriate channel used to enable devices tocommunicate wirelessly, such as Bluetooth, cellular, NFC, or Wi-Fichannels. It should be understood that the device can have one or moreconventional wired communications connections as known in the art. Thedevice also includes one or more power components 908, such as mayinclude a battery operable to be recharged through conventional plug-inapproaches, or through other approaches such as inductive or wirelesscharging through proximity with a power mat or other such device. Insome embodiments the device can include at least one additionalinput/output device 910 able to receive conventional input from a user.This conventional input can include, for example, a push button, touchpad, touch screen, wheel, joystick, keyboard, mouse, keypad, or anyother such device or element whereby a user can input a command to thedevice. These I/O devices could even be connected by a wireless infraredor Bluetooth or other link as well in some embodiments. Some devicesalso can include a microphone or other audio capture element thataccepts voice or other audio commands. For example, a device might notinclude any buttons at all, but might be controlled only through acombination of visual and audio commands, such that a user can controlthe device without having to be in contact with the device.

As mentioned, many embodiments will include at least some combination ofone or more emitters 916 and one or more detectors 918 for measuringdata for one or more metrics of a human body, such as for a personwearing the tracker device. In some embodiments this may involve atleast one imaging element, such as one or more cameras that are able tocapture images of the surrounding environment and that are able to imagea user, people, or objects in the vicinity of the device. The imagecapture element can include any appropriate technology, such as a CCDimage capture element having a sufficient resolution, focal range, andviewable area to capture an image of the user when the user is operatingthe device. Methods for capturing images using a camera element with acomputing device are well known in the art and will not be discussedherein in detail. It should be understood that image capture can beperformed using a single image, multiple images, periodic imaging,continuous image capturing, image streaming, etc. Further, a device caninclude the ability to start and/or stop image capture, such as whenreceiving a command from a user, application, or other device. Theexample device includes emitters 916 and detectors 918 capable of beingused for obtaining other biometric data, which can be used with examplecircuitry discussed herein.

If included, a display 906 may provide an interface for displaying data,such as heart rate (HR), ECG data, blood oxygen saturation (SpO₂)levels, and other metrics of the user. In an embodiment, the deviceincludes a wristband and the display is configured such that the displayfaces away from the outside of a user's wrist when the user wears thedevice. In other embodiments, the display may be omitted and datadetected by the device may be transmitted using the wireless networkinginterface via near-field communication (NFC), Bluetooth, Wi-Fi, or othersuitable wireless communication protocols over at least one network 920to a host computer 922 for analysis, display, reporting, or other suchuse.

The memory 904 may comprise RAM, ROM, FLASH memory, or othernon-transitory digital data storage, and may include a control programcomprising sequences of instructions which, when loaded from the memoryand executed using the processor 902, cause the processor 902 to performthe functions that are described herein. The emitters 916 and detectors918 may be coupled to a bus directly or indirectly using drivercircuitry by which the processor 902 may drive the light emitters 916and obtain signals from the light detectors 918. The host computer 922communicates with the wireless networking components 912 via one or morenetworks 920, which may include one or more local area networks, widearea networks, and/or internet, using any of terrestrial or satellitelinks. In some embodiments, the host computer 922 executes controlprograms and/or application programs that are configured to perform someof the functions described herein.

In various embodiments, approaches discussed herein may be performed byone or more of: firmware operating on a monitoring or tracker device ora secondary device, such as a mobile device paired to the monitoringdevice, a server, host computer, and the like. For example, themonitoring device may execute operations relating to generating signalsthat are uploaded or otherwise communicated to a server that performsoperations for removing the motion components and creating a finalestimate value for physiological metrics. Alternatively, the monitoringdevice may execute operations relating to generating the monitoringsignals and measuring the motion components to produce a final estimatevalue for physiological metrics local to the monitoring device. In thiscase, the final estimate may be uploaded or otherwise communicated to aserver such as host computer that performs other operations using theestimate.

An example monitoring or tracker device can collect one or more types ofphysiological and/or environmental data from one or more sensor(s)and/or external devices and communicate or relay such information toother devices (e.g., host computer or another server), thus permittingthe collected data to be viewed, for example, using a web browser ornetwork-based application. For example, while being worn by the user, atracker device may perform biometric monitoring via calculating andstoring the user's step count using one or more sensor(s). The trackerdevice may transmit data representative of the user's step count to anaccount on a web service (e.g., www.fitbit.com), computer, mobile phone,and/or health station where the data may be stored, processed, and/orvisualized by the user. The tracker device may measure or calculateother physiological metric(s) in addition to, or in place of, the user'sstep count. Such physiological metric(s) may include, but are notlimited to: energy expenditure, e.g., calorie burn; floors climbedand/or descended; HR; heartbeat waveform; HR variability; HR recovery;respiration, SpO₂, blood volume, blood glucose, skin moisture and skinpigmentation level, location and/or heading (e.g., via a GPS, globalnavigation satellite system (GLONASS), or a similar system); elevation;ambulatory speed and/or distance traveled; swimming lap count; swimmingstroke type and count detected; bicycle distance and/or speed; bloodglucose; skin conduction; skin and/or body temperature; muscle statemeasured via electromyography; brain activity as measured byelectroencephalography; weight; body fat; caloric intake; nutritionalintake from food; medication intake; sleep periods (e.g., clock time,sleep phases, sleep quality and/or duration); pH levels; hydrationlevels; respiration rate; and/or other physiological metrics.

An example tracker or monitoring device may also measure or calculatemetrics related to the environment around the user (e.g., with one ormore environmental sensor(s)), such as, for example, barometricpressure, weather conditions (e.g., temperature, humidity, pollen count,air quality, rain/snow conditions, wind speed), light exposure (e.g.,ambient light, ultra-violet (UV) light exposure, time and/or durationspent in darkness), noise exposure, radiation exposure, and/or magneticfield exposure. Furthermore, a tracker device (and/or the host computerand/or another server) may collect data from one or more sensors of thedevice, and may calculate metrics derived from such data. For example, atracker device may calculate the user's stress or relaxation levelsbased on a combination of HR variability, skin conduction, noisepollution, and/or sleep quality. In another example, a tracker devicemay determine the efficacy of a medical intervention, for example,medication, based on a combination of data relating to medicationintake, sleep, and/or activity. In yet another example, a tracker devicemay determine the efficacy of an allergy medication based on acombination of data relating to pollen levels, medication intake, sleepand/or activity. These examples are provided for illustration only andare not intended to be limiting or exhaustive.

An example monitoring device may include a computer-readable storagemedia reader, a communications device (e.g., a modem, a network card(wireless or wired), an infrared communication device) and workingmemory as described above. The computer-readable storage media readercan be connected with, or configured to receive, a computer-readablestorage medium representing remote, local, fixed and/or removablestorage devices as well as storage media for temporarily and/or morepermanently containing, storing, transmitting and retrievingcomputer-readable information. A monitoring system and various devicesalso typically will include a number of software applications, modules,services or other elements located within at least one working memorydevice, including an operating system and application programs such as aclient application or Web browser. It should be appreciated thatalternate embodiments may have numerous variations from that describedabove. For example, customized hardware might also be used and/orparticular elements might be implemented in hardware, software(including portable software, such as applets) or both. Further,connection to other computing devices such as network input/outputdevices may be employed.

Storage media and other non-transitory computer readable media forcontaining code, or portions of code, can include any appropriate mediaknown or used in the art, such as but not limited to volatile andnon-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such as computerreadable instructions, data structures, program modules or other data,including RAM, ROM, EEPROM, flash memory or other memory technology,CD-ROM, digital versatile disk (DVD) or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices or any other medium which can be used to store thedesired information and which can be accessed by a system device. Basedon the disclosure and teachings provided herein, a person of ordinaryskill in the art will appreciate other ways and/or methods to implementthe various embodiments.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. It will, however, beevident that various modifications and changes may be made thereuntowithout departing from the broader spirit and scope of the invention asset forth in the claims.

1. (canceled)
 2. A wearable device comprising: a biometric circuitconfigured to monitor one or more biometrics of a user wearing thewearable device; a first conductive element; a first decoupling elementconfigured to selectively couple the first conductive element to thebiometric circuit such that the first conductive element operates as anelectrode for the biometric circuit; and a second decoupling elementconfigured to selectively couple the first conductive element to anelectrical ground such that the first conductive element operates as anantenna.
 3. The wearable device of claim 2, wherein the first decouplingelement comprises a resistor, a capacitor, or an inductor.
 4. Thewearable device of claim 2, wherein the second decoupling elementcomprises a capacitor.
 5. The wearable device of claim 2, wherein thebiometric circuit comprises an electrocardiogram (ECG) circuit.
 6. Thewearable device of claim 2, further comprising: a first antenna matchingcircuit coupled between the second decoupling element and the electricalground.
 7. The wearable device of claim 6, further comprising: a secondantenna matching circuit that is separate from the first antennamatching circuit; and a second conductive element that is different fromthe first conductive element, the second conductive element electricallycoupled to the second antenna matching circuit.
 8. The wearable deviceof claim 7, wherein: the first conductive element is capacitivelycoupled to the second conductive element when the first conductiveelement is coupled to the first antenna matching circuit via the seconddecoupling element.
 9. The wearable device of claim 2, wherein the firstconductive element is part of a housing of the wearable device.
 10. Thewearable device of claim 2, wherein the antenna comprises a parasiticantenna.
 11. An electronic device comprising: a biometric circuitconfigured to monitor one or more biometrics of a user; a firstconductive element; a first decoupling element configured to selectivelycouple the first conductive element to the biometric circuit such thatthe first conductive element operates as an electrode for the biometriccircuit; and a second decoupling element configured to selectivelycouple the first conductive element to an electrical ground such thatthe first conductive element operates as an antenna.
 12. The electronicdevice of claim 11, wherein the first decoupling element comprises aresistor, a capacitor, or an inductor.
 13. The electronic device ofclaim 11, wherein the second decoupling element comprises a capacitor.14. The electronic device of claim 11, wherein the biometric circuitcomprises an electrocardiogram (ECG) circuit.
 15. The electronic deviceof claim 11, further comprising: a first antenna matching circuitcoupled between the second decoupling element and the electrical ground.16. The electronic device of claim 15, further comprising: a secondantenna matching circuit that is separate from the first antennamatching circuit; and a second conductive element that is different fromthe first conductive element, the second conductive element electricallycoupled to the second antenna matching circuit.
 17. The electronicdevice of claim 16, wherein: the first conductive element iscapacitively coupled to the second conductive element when the firstconductive element is coupled to the first antenna matching circuit viathe second decoupling element.
 18. The electronic device of claim 11,wherein the first conductive element is part of a housing of theelectronic device.
 19. The electronic device of claim 11, wherein theantenna comprises a parasitic antenna.